Smoked some wires today

A1B goes to the fusible link and then inside to the main splice etc..
S5 (12 ga brown) goes to the starter solenoid.
The only place they could be touching is in the engine compartment where they run next to each other along the fender.
But what happened, happened with the key was in Start. So this doesn't make sense - at least not yet to me.
See above posts

Do you have any tips on looking through the rest of the wiring on the dash side? I checked continuity across several points at the connector on the dash side and got beeps. I'm not sure if they're supposed to be electrically touching. Is it just getting under there with the chassis guide and figure out what shouldn't be touching? Thanks in advance